China has shut down dozens of illegal or unsanitary blood collection stations as part of its efforts to curb the spread of AIDS in the country.

State media say a special task force is inspecting blood collection stations across China. The task force has recently closed down 52 illegal centers.

The Chinese government has blamed poor practices at blood banks as one of the major causes of the AIDS epidemic in this country. Throughout the 1990s, many poor farmers in some villages sold their blood to blood banks. The banks pooled the blood of several people in to a single container, extracted the plasma needed for transfusions, and transfused the remaining mixed blood back in the donors.

This method allowed donors to rebuild their blood cells sooner, so they could sell blood more often. But it also gave the HIV virus that causes AIDS an easy route to spread rapidly.

The chief of the health and nutrition section of UNICEF office for China, Koen Vanormelingen, says the Chinese government, which for years denied the country had an AIDS problem, now is trying to prevent such disasters.

"I would say they have learned their lesson with regards to the transmission of HIV/AIDS through plasma donors and blood sale, and the government is very much aware about the issue and trying as much as possible to control it," said Mr. Vanormelingen.

Since 1998, when a new law banned using blood from paid donations, China has suffered a shortage of blood.

"The supply of the official blood is not sufficient at this moment because they are changing the law with regards with blood donation," Koen Vanormelingen explained. "Now the Red Cross and other facilities are dependent on voluntary donation."

The Chinese government has run publicity campaigns in the past few years to encourage voluntary blood donation, but so far, they have not helped close the gap between supply and demand.

China says it has an estimated 840,000 HIV/AIDS patients, of which around 20 percent are believed to have been infected through unsanitary blood collection.